1. Field of the Invention
The present invention relates to semiconductor integrated circuits, and in particular to integrated circuits used in devices providing multiple purposes to end users, such as television, audio, Internet access, telephone service and the like.
2. Description of the Related Art
Increasingly, consumer products are being developed as multiple purpose devices. Examples include using mobile telephones to function as MP3 players, cameras & radios, using portable storage devices as media players and using television “set top boxes” as devices to access the Internet and provide telephone services. In such devices, the different purposes can be provided by different integrated circuits, or increasingly by multiple purpose integrated circuits.
Integrated circuits (computer chips) that support digital television often have extensive mechanisms for protecting encrypted data against viewing or distribution by or to devices that are not entitled to do so. These “conditional access” systems employ a significant amount of hardware to protect these systems against attack by persons wanting to view, distribute or sell systems that can circumvent security for third parties.
Computer chips that support cable modem applications, which deliver high-speed Internet access using a common cable with the cable that delivers digital television, also support security mechanisms. The drive for cost reduction through super-integration and the focus that cable companies have on selling multiple services to each consumer (telephone, television and internet) has lead to the integration of cable modem and set-top box functions in a single chip.